Hi!
The tank should be mounted in lots of soft foam...not the white stuff!.
In a ARF the tank is mostly pushed in and forgotten...

As for glowplugs forget the FOX idle-bar plug. Your engine will work much better if you use an OS 8 or Enya 3 glowplug. These are the two glowplugs that all sport engines will work good on.
Of course there are other plugs too that are good but using one of these will make your engine run good for a long time.
As for props start out with the 10x6. The 11x7 is way to large...do not use it!
The 10x6 Master Airscrew isn't that good though (noisy and bad performance) There are other props that are much better, like APC, Kyosho, Graupner Cam-prop and RAM.
Remember that the 10x6 prop isn't the ideal prop for all airplanes. For a high winged trainer a 11x5, 11x6 or 12x4 APC is the prop size to choose.
For a smaller low winged airplane (around 130cm in span) a 10x6 or a 10x7 APC is the preferred prop.

Regards!
Jan K
Sweden